1. Field of the Invention
The present invention relates to a handover method between a femto base station and a macro base station.
2. Description of the Related Art
Active research has recently been done on a base station that manages small cells within a macrocell coverage area. The small cell is referred to as a femtocell, and a base station managing the femtocell is referred to as a femto base station. For example, when a femto base station is installed indoors, a user of a mobile communication system can be provided with service through a macro base station outdoors and can be provided with service through the femto base station indoors.
The femto base station is constructed to have a small cell radius (e.g., about 30 m). Many femto base stations can be installed within a macrocell coverage area. The femto base station is unable to control power in detail like a macro base station, and is also unable to perform proper cell planning at a system level. Accordingly, when a terminal seeks to connect to a femto base station located close to a macro base station or a femto base station located in an area where a high intensity signal is received from a macro base station, a problem can occur during handover. Although the terminal enters a coverage area of the femto base station, if a difference between the intensity of a signal received from the macro base station and the intensity of a signal received from the femto base station is not greater than a certain range or more, the terminal remains connected to the macro base station.
Accordingly, when a macro base station and a femto base station coexist in the same environment, and a terminal seeks to connect to a femto base station located close to the macro base station or a femto base station located in an area where a high intensity signal is received from the macro base station, a method of performing handover between the terminal and the femto base station is desired.